# Evolutionary and Functional Insights into Rice Universal Stress Proteins in Response to Abiotic Stresses

## TL;DR

This paper identifies and studies rice stress proteins that help the plant survive harsh conditions, offering targets for breeding more resilient rice.

## Contribution

The study provides a genome-wide characterization of rice Universal Stress Proteins and identifies key genes responsive to multiple abiotic stresses.

## Key findings

- 46 OsUSP genes were identified and classified into three subfamilies with distinct structural and functional features.
- LOC_Os02g54590 and LOC_Os05g37970 are strongly induced under all tested stress conditions, suggesting their importance in stress adaptation.
- OsUSPs are involved in hormonal and stress signaling pathways, with potential interactions in phosphorylation and stress response networks.

## Abstract

This study aimed to identify and characterize the Universal Stress Protein (USP) family in rice, a group of proteins known to mediate adaptation to harsh environments. We found 46 of these OsUSP genes in the rice genome and studied their characteristics, evolutionary relationships, and how they are turned on under stress. Our results show that these genes are activated by different stresses and are likely crucial for helping rice survive difficult conditions. Notably, LOC_Os02g54590 and LOC_Os05g37970 were strongly induced under all tested stress conditions, making them promising targets for genetic engineering and molecular breeding programs. This research provides a valuable foundation for future work aimed at improving the stress resistance of rice, offering potential strategies to develop more resilient rice varieties, which is vital for ensuring global food security in the face of climate change.

Universal Stress Protein (USP) plays crucial roles in plant stress adaptation, yet their evolutionary dynamics, regulatory mechanisms, and functional diversification in rice (Oryza sativa) remain poorly understood. This study aimed to conduct a genome-wide identification and characterization of the OsUSP gene family to elucidate its role in abiotic stress responses using integrated bioinformatics approaches. Here, we identified 46 OsUSP genes that are unevenly distributed across 11 rice chromosomes and exhibit significant divergence in protein length, molecular weight, and subcellular localization. Phylogenetic analysis classified OsUSPs into three subfamilies, with conserved motif and domain architectures within groups but distinct structural variations across subfamilies. Evolutionary analysis revealed strong collinearity between rice and other monocots, which suggests functional conservation in grasses, whereas limited synteny with dicots indicates lineage-specific divergence. Cis-regulatory element analysis showed enrichment in ABA, MeJA, drought, and hypoxia response motifs, implicating OsUSPs in hormonal and stress signaling. Expression profiling indicated tissue-specific patterns, with subfamily III genes broadly expressed, while subfamily II members were anther-enriched. Stress response profiling revealed that 24 OsUSPs were significantly induced, while LOC_Os02g54590 and LOC_Os05g37970 emerged as particularly notable due to their broad-spectrum responsiveness, being upregulated under all tested stress conditions. Protein–protein interaction (PPI) analysis indicated that OsUSP proteins potentially interact with Leo1/TPR-domain proteins and are involved in stress response and phosphorylation signaling pathways. This study yields key insights into OsUSP-mediated stress adaptation in rice and pinpoints promising candidate genes to facilitate the breeding of climate-resilient rice.